Differences in Process#destroy() between Windows and Unix implementations

[Anthony Petrov]

On 11/10/2010 1:48 PM, Rémi Forax wrote:
> The soft way to kill a process on windows to send a WM_CLOSE/WM_QUIT.
> http://stackoverflow.com/questions/2055753/how-to-gracefully-terminate-a-process

This only works for GUI applications that process window messages (e.g. 
AWT or Swing apps). If an application is GUI-less and doesn't create 
native windows, there's nothing to send this message to.

--
best regards,
Anthony

>
> Rémi
>
>
> Le 10/11/2010 10:46, Andreas Kohn a écrit :
>> On Wed, 2010-11-10 at 06:02 +1000, David Holmes wrote:
>>
>>> Hi Andreas,
>>>
>>> On 10/11/2010 5:31 AM, Andreas Kohn wrote:
>>>
>>>> there seems to be a difference in behavior between Process#destroy()
>>>> implementations on Windows and !Windows: on Windows TerminateProcess()
>>>> [1] is called, which gives the process no way to react or in any way
>>>> intercept the termination, while on Unix a simple SIGTERM is send which
>>>> the process can just decide to ignore. [2]
>>>>
>>>> Is this intentional?
>>>>
>>> As I understand it: yes and no. :)
>>>
>>> The problem is that neither version is necessarily what you always want.
>>> SIGTERM is nice in that it allows the process to execute cleanup handlers
>>> etc (such as an exec'ed JVM!) but I don't think Windows has an equivalent,
>>> so we have to use TerminateProcess. On the flip side if SIGTERM fails we
>>> have no way to really kill an errant process.
>>>
>>>
>> Thanks for the confirmation that this is an unfortunate leak of the OS
>> details into the java library. Looking through the bugdatabase I found
>> various related bugs now, so I did not file a new RFE just now:
>>
>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4073195
>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4333183
>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6960070
>>
>>
>>> What we really need is two destroy methods: one that tries to
>>>
>> terminate
>>
>>> nicely and one with "extrene prejudice". But again I'm not sure that Windows
>>> would support that. I suppose we could also define the destroy() method to
>>> try both approaches, if available, eg SIGTERM wait a while SIGKILL. But then
>>> we need a way to specify "wait a while".
>>>
>> I think if you have the ability as API user to indicate to Process
>> whether it should "stop, please" or "die!" it would be perfectly enough.
>>
>> Windows may not provide the APIs for the "please" part, but then again
>> this is as mentioned above and in the bugs very system specific, so
>> having the Windows implementation do nothing in the "please" case should
>> be fine, as this would be still classify as "best effort".
>>
>> Windows:
>> Process#stop() {
>>    // nothing, windows doesn't do it
>> }
>> Process#destroy() {
>>    TerminateProcess();
>> }
>>
>> Unix:
>> Process#stop() {
>>    kill(SIGTERM);
>> }
>> Process#destroy() {
>>    kill(SIGKILL);
>> }
>>
>> Regards,
>> --
>> Andreas
>>
>>
>>> David Holmes
>>>
>>>
>>>> I do prefer the Windows behavior, mainly because I do create processes
>>>> once in a while that simply fail to terminate due to bugs in their
>>>> implementation, and having Process#destroy() as a last, and terminal,
>>>> resort is very helpful to work-around those issues.
>>>>
>>>> Regards,
>>>> --
>>>> Andreas
>>>>
>>>> [1]
>>>> http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/d87c1c06bbf9/src/windows/native/java/lang/ProcessImpl_md.c
>>>> [2]
>>>> http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/d87c1c06bbf9/src/solaris/native/java/lang/UNIXProcess_md.c
>>>>
>>>>
>>>>
>>
>